Metal cleaning composition



Patented June 22, 1 937 UNITED STATES." PATENTOFFICE I 2,084,361 METAL CLEANING oomosrnon Byron M. Vanderbilt, Chicago-Heights, 111., as-

signor'to Victor Chemical Works, a corporation oi Illinois No Drawing. Application December 17, 1934, v I Serial No. 757,971

. 1e Claims. (cl, -1488) This invention relates to a metal cleaning comequal m le ular am n r p p position, and more particularly to metal cleanphoric acid was added in a thin stream under ing compositions comprising esters of phosphoric o d gitation at a temperature below 35 0. acid. The reaction was exothermic, but not extremely orthophosphoric acid has been considerably running ap er uffl in as a cooling 5 used heretofore for the removal of oil and rust means- The tWO reactants mixed di y to v from ferrous metals, frequently in admixture a yellow solution. When the addition of the acid with organic solvents such as aliphatic alcohols, Was complete, t so u n was allowed to stand the latter serving thepurposeof emulsifying or from 24-48 hQurS When a I upy P o uct 10 dissolving adhering Oil or grease, while t phos; was obtained. The product was miscible in water 10 phoric i removed t t, and could be used in dilute solution as a clean- In this connection it has been recognized that 8 d derusting agent for ferrous metalsthe higher alcohols such as butyl and amyl are 83 grams of normal amyl alcohol Were superior as grease solvents to the lower alcohols, afited with an equal molar Weight of py p sbut their use has been limited because of their acid (178 grams) in a manner Similar to 15 1 a the above experiment except that it was possible igzfi g t g g solubility m aqueous'pho'sphor to increase the reaction temperature topabout It has now been discovered that these ,difiicul- 0- without decomposition The reaction 1 ties may be avoided, and a superior degreasing H may he storfd at a temperature ranging and derusting Solution prepared by reacting on between 40 and 60 C. for 10 to 48 hours in order 20 the primary alcohols [with pyro or metaphos to complete the reaction. A dark brown viscous phoric acids, or a combination thereof, to form h d was obtained wlth specific gravity or monophosphoric acid esters. The pyro and met- 1-323. 'he iquid could be diluted with 9 parts or aphosphoric acids are herein referred to as def becommg turbid and even at this hydrated phosphoric with dilution was an excellent dcgreasing and derust- The reaction between the pyrophosphoric acid mg agentn and the primary aliphatic alcohols is believed to 176 grams of refined fuse] Oil Which was take place substantially according to the followcomposed of nearly pure active amyl and isolng equations: amyl alcohols, was reacted with 392 grams of pyrophosphoric acid at a temperature below 40 30 H4P2O7+ROH=RH2P04+H3PO4 C. The reaction mixture was then allowed to age Thus, for every mol. of the monophosphoric acid at about for 18 Product was ester formed in the reaction with pyrophosphoric similar to t Prepared except that it acid, there is also formed one mol. of orthophoscu1d only be diluted with 7 Parts of Water before phone cloudiness occurred. 35

In the case of metaphosphoric acid, the reac- Crude fusel 011 t ning about 60-65% of tion apparently is according to the following amyl alcohds with the rest Water f lower equati n: cohols was also used, and resulted in a fairly HPO3+ROH=RH2PO4, satisfactory product except that it could not be used in dilution greater than about 1 part to 40 It is believed that the above reactions substan- 3 parts of wat r, tially represent the net results of the reactions, 5, 35 grams 1 rmal butane] were added to but it isnot known whether intermediate reac- 40 grams of 88% metaphosphorlc acid and tions occur with subseq en hydrolysis to form stirred at 40 C. until well mixed. on standing the mono esters, or to what extent the prodt 40 for for 12 hours one phase was buct is contaminated with traces of esters of the tainei The product was semble t maximum 1- dehydrated phosphoric a lution with 6 volumes of water, and the aqueous The reaction products have decr a in and desolution could be diluted with 75% phosphoric us Characteristics Which are Similar in the acid solution without precipitation of the ester.

two cases. Apparently the reaction proceeds in I 6, 40 grams of 88% metaphosphoric acid and 50 accordance with the above equation to yield sub-- 36 grams of refined fuse] oil were'mixed at 40 stantially the mono esters. The temperature in c, n h t t 40 C for 43 hours, T prodall cas s sh u d be pt s fli n ly w t a id not was soluble in water to the extent of 1 part charring and possible ether formation. in 7 parts of water. The aqueous solution was 5 Several examples of the preparation of metal a fairly good metal cleaner provided the metal cleaning and derusting solutions in accordance was only slightly rusty. The product could be with the invention are as follows: diluted with orthophosphoric acid without pre- 1. 223 grams of pure butanol were placed in a cipitation. one liter three neck flask equipped with stirrer, The reaction products of pyrophosphoric acid 0 thermometer, and external cooling means. An and methanol; ethyl alcohol, and normal propyl e0 agents as alcohol were also prepared, but these products were notas good as metal cleaning and derusting I the reaction products'of pyrophosphoric acid and the primary amyl and butyl alcohols.

Pyrophosphoric acid will react readily with any of the primary alcohols containing less than 7 carbon atoms and with many of the organic compounds containing the primary alcohol group, as glycerine, glycol, butyl ether of ethylcne glycol, to form water soluble reaction products with metal cleaning and derusting properties. The higher alcohols such as capryl, lauryl, and cetyl alcohols do not readily react under the above conditions.

In the reactions of pyrophosphoric and metaphosphoric acids with butanol, it is desirable to keep the temperature below 50 C. to prevent charring and formation of ether. In the case of the amyl alcohols the reaction temperature should be held under 60 C. with pyrophosphoric acid and 50 C. with metaphosphoric acid.

The reaction of the primary alcohols with pyro and metaphosphoric acids is clearly indicated by numerous tests to be definite chemical combinations and no admixtures.

It is preferred to use the reaction product of pyrophosphoric and metaphosphoric acids with primary butyl and amyl alcohols as metal cleaning solutions. These products may be diluted with orthophosphoric acid to suit the conditions under whichthey are to be used. For example, if the metals to be cleaned are contaminated with large quantities of oil or grease the concentration of the butyi or amyl phosphate should be high, while on the other hand, if considerable rust is to be removed the phosphoric acid concentration should be high, additional orthophosphoric acid being added if necessary. However, this is usually not necessary with the pyrophosphoric acid reaction product because of the formation of free orthophosphoric acid in the reaction. In the case of the alcohol metaphosphoric acid product, it is often phosphoric acid.

In some cases it may be desirable to increase the oil or grease removing capacity by adding to the reaction products mentioned above, one of the lower water soluble alcohols such as methyl, ethyl, or propyl alcohol. Such a product would have all of the advantages due to the ester in addition to the oil emulsifying power of the lower alcohols.

One of the primary uses to which the solutions may be applied is that of cleaning automobile bodies and the like prior to their being painted. The metal parts may be dipped or sprayed with a relatively dilute aqueous solution of the product preferably containing about 15-25% of the reaction product. This solution is allowed to remain on the metal a few minutes or sufliciently long to remove the rust and oil, and is then either washed or wiped thoroughly before applying paint.

In using the above solutions as rust and grease removing compositions, an additional advantage is accomplished in that the resultant metal surface is rust-proofed to a considerable degree by the formation of a thin phosphate coating.

While the above description has been largely confined to a discussion of a composition for the removal of oils and rust from ferrous metals, it has been found that such compositions also remove oil and corrosion matter from metals such as tin, brass and copper.

desirable to add ortho- The foregoing detailed description is given for clearness of understanding only, and no unnecessaryllimit'ations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

What I regard as new and desire to secure by Letters Patent is:

' 1. A metal cleaning solution comprising the water soluble acid esteric reaction product of a dehydrated phosphoric acid and an organic compound containing a primary alcohol group.

2. A metal cleaning composition comprising the acid esteric reaction product of a dehydrated phosphoric acid and butanol.

3. A metal cleaning composition comprising the acid esteric reaction product of a dehydrated phosphoric acid and a primaryamyl alcohol.

4. A metal cleaning composition comprising an ester of a primary alcohol and a phosphoric acid, together with orthophosphoric acid.

5. A composition as set forth in claim 4, in which the solu ion comprises a major proportion of water.

6. A metal cleaning composition comprising an ester of a primary alcohol and a phosphoric acid, together with a water soluble aliphatic alcohol.

'1. A metal cleaning composition comprising an ester of a primary alcohol and a phosphoric acid, together with a water soluble aliphatic alcohol and orthophosphoric acid.

8. A metal cleaning composition comprising the phosphoric reaction product of a primary aliphatic alcohol and a mixture of metaphosphoric and pyrophosphoric acids.

9. In the formation of a metal cleaning solution comprising phosphoric acid and the esterifled reaction product of meta and pyrophosphoric acids and a primary aliphatic alcohol, the step of controlling the ratio of phosphoric acid to the esterified product by controlling the ratio of meta and pyrophosphoric acids to each other.

10. A metal cleaning solution comprising the phosphoric reaction product of fusel oil and a dehydrated phosphoric acid.

11. The method of forming a metal cleaning solution which comprises mixing a molecularly dehydrated phosphoric acid with an organic compound containing a primary alcohol group whereby they react to form an acid ester product.

12. The method of forming a metal cleaning solution which comprises mixing a molecularly dehydrated phosphoric acid with a primary aliphatic alcohol containing less than seven carbon atoms whereby they react to form an acid ester product.

13. The method-as set forth in claim 12, in which reaction is carried out at a low temperature.

14. The method of forming monophosphoric acid esters which comprises mixing a molecularly dehydrated phosphoric acid with an organic compound containing a primary alcohol group whereby they react to form an acid ester.

15. A metal cleaning composition comprising an ester of an organic compound containing a primary alcohol group and a phosphoric acid, and orthophosphoric acid.

16. A metal cleaning composition comprising orthophcsphoric acid and an ester of a primary alcohol containing from 4 to '7 carbon atoms and a phosphoric acid. 

